1. Field of the Invention
This invention relates to penetration resistant garments and more particularly to lightweight, high-pressure water jet penetration resistant garments.
2. Related Art
Industrial tools utilizing high pressure water jets continue to be developed, such as, for example, metal working and cutting tools in which the water jet is fixed and the workpiece is moved relative to the water jet. Other tools, for example, hand-held gun-like water jet lances in which the operator moves the water jet over a stationary workpiece, have also been developed. These lances are used, for example, to remove coatings, such as paint, from metallic surfaces. In both types of tools, high pressure water pumps capable of delivering up to 40,000 psi supplies the high pressure water to the jet. With increased operating pressures, the overall horsepower of the pumps has also increased, which has resulted in an increase in water flow rates.
The increase in pressure and flow has increased the risk of serious injury from direct cuts or amputations and infections, especially when using the hand-held water jet lance, for example. Not only does the water jet contain very large energies that will penetrate body tissue very aggressively, the water jet may carry dirt and bacteria into the wound beyond the region of obvious tissue damage.
The water jet can be thought of as a needle-like penetrator because the diameter of the jet is small. However, unlike a needle, which is defeated when the tip is bent, a water jet continuously renews the sharp focus of penetration. Conventional cut resistant or bullet proof garments offer little protection from a water jet because the fabrics used in such garments are readily cut and eroded by the jet's small intense contact point such that full penetration may occur. In general, once penetration has started, the erosive effect of the water jet destroys all of the remaining fabric at the contact point. As a result, the use of high performance fabrics having open, flexible weaves make such fabrics poor candidates for use in protective garments for water jet applications.
Rigid steel or aluminum would offer protection from the erosion of the water jet. However, in addition to the added weight, such materials significantly compromise comfort and freedom of motion and thus are gene rally not suitable for use in protective garments, especially in industrial environments where such characteristics are necessary.
Given the risk in this industry, a number of attempts at safety garments have been developed. DuPont and others, for example, have developed lined suits using penetration resistant fabrics. An example of such a fabric is disclosed in U.S. Pat. Nos. 5,565,264 and 5,837,623, which are assigned to the present assignee and which are incorporated herein by reference in their entireties. The suits made from such fabrics are shaped and formed using conventional techniques. For example, the front of the pant of the suit is cut from a continuous piece of the penetration resistant fabric. Alternatively, the penetration resistant fabric may be added as a liner following the basic shape of the outer layer of the garment.
To provide a desired level of penetration resistance while retaining some flexibility, multiple layers of penetration resistant fabric are used. However, these added layers significantly add to the cost and weight of the garment. In addition, the suits, which cover the entire body, tend to hold heat and reduce the evaporative cooling of the wearer, which may result in heat stress.